A package in which a semiconductor chip is provided on an insulating film on which a wiring pattern is formed, such as a TCP (Tape Carrier Package) or a COF (Chip on Film), is widely used as a package for an LCD driver which is attached to a liquid crystal panel or the like. Examples of the LCD driver encompass: a source driver for supplying a signal to a source electrode of a transistor provided in a pixel region in a liquid crystal panel; and a gate driver for supplying a signal to a gate electrode of the transistor.
FIG. 7 is a view schematically illustrating an arrangement of a conventional liquid crystal module 500.
The conventional liquid crystal module 500 includes a liquid crystal panel 501, gate drivers 502, source drivers 503, and input substrates 504 (see FIG. 7). A plurality of source drivers 503 are attached to one or two of four sides of the liquid crystal panel 501. A plurality of gate drivers 502 are attached to, among the four sides of the liquid crystal panel 501, one or two sides which are perpendicular to the side(s) to which the plurality of source drivers 503 are attached. The input substrates 504 are provided to be opposite to the liquid crystal panel 501 with respect to the source drivers 503.
In the arrangement, the gate drivers 502 and the source drivers 503 receive a drive signal and a power source from wiring lines provided on the input substrate 504. Thereby, the liquid crystal panel 501 is driven. That is, in the liquid crystal module 500, the gate driver 502 receives the drive signal and the power source from the input substrate 504 via the source drivers 503 and the liquid crystal panel 501 (see Patent Literature 1, for example).
FIG. 8 is a view illustrating an arrangement of a conventional source driver 503.
The conventional source driver 503 includes a semiconductor chip 514, and has a region segmented into four regions: an input terminal wiring region 511 in which wiring lines are provided so as to be connected to input terminals of the semiconductor chip 514, respectively; an output terminal wiring region 512 in which wiring lines are provided so as to be connected to output terminals of the semiconductor chip 514, respectively; and two through wiring regions 513.
The following description explains how to manufacture the source driver 503. First, a long carrier tape is subjected to a series of manufacturing processes. The long carrier tape has sprocket portions 515, each of which has a string of holes. The sprocket portions are provided at ends of the long carrier tape, which ends face each other in a width direction. After the manufacturing processes, parts which are to be the source drivers 503 are cut out. Thus, individual source drivers 503 are manufactured (see FIG. 9). The sprocket portions 515 are used as carrier members of the long carrier tape. The sprocket portions are used when the long carrier tape is reeled in/out. A user uses only the cut out part of the long carrier tape, as the source driver 503. The other parts of the long carrier tape, such as the sprocket portions 515, are discarded.
The source driver 503 is attached to the liquid crystal panel such that the output terminal wiring region 512 extends toward the liquid crystal panel 501 (see FIG. 10). The input terminals of the semiconductor chip 514 and wiring lines of the input substrates 504 are connected to each other, respectively, via the wiring lines of the input terminal wiring region 511. The output terminals of the semiconductor chip 514 and wiring lines of the liquid crystal panel 501 are connected to each other, respectively, via the wiring lines of the output terminal wiring region 512.
Wiring lines for supplying a signal and the power source to the gate drivers 502 are provided in each of the through wiring regions 513. The gate driver 502 is driven by the signal received from the input substrate 504 via the through wiring region 513 of the source driver 503 (see an arrow X). That is, the through wiring region 513 of the source driver 503 is provided to supply a drive signal and the power source to the gate driver 502.
The plurality of source drivers 503 are attached to the single liquid crystal panel 501, as described above. However, only through wiring regions 513 of two source drivers provided at both ends of the side of the liquid crystal panel 501 are in use for the purpose described above (see FIG. 7). The through wiring regions 513 of the other source drivers 503 are out of use. For example, in FIG. 10, a left through wiring region 513 of a source driver 503a is in use, but a right through wiring region 513 of the source driver 503a, and both through wiring regions 513 of a source driver 503b are out of use.
The semiconductor chip 514 of the source driver 503 generates heat. Such heat is (i) dissipated from the semiconductor chip 514 itself, (ii) dissipated from the wiring lines themselves provided in the input terminal wiring region 511, (iii) led toward the input substrate 504 via the wiring lines provided in the input terminal wiring region 511, (iv) dissipated from the wiring lines themselves provided in the output terminal wiring region 512, and (v) led toward the liquid crystal panel 501 via the wiring lines provided in the output terminal wiring region 512.